The Telescope
History and Overview
JASON
ALEX
JAMES
DUGAN
Background
 Ptolemy first wrote about Optics in the 2nd Century,
and it was known that water filled glass caused
‘distortions’ in objects visible through them.
History
 Reading Stones and Burning Glasses were used
throughout Europe starting in the 12th Century.
 Glasses were invented during this time!
History (cont.)
 Finally, in the first years of the 17th Century, a trio of
Dutch inventors wondered what would happen if you
were to put these lenses in sequence? The result –
the first Telescope.
They called it the
‘Perspective Glass’.
Downside? Only had
3x Magnification!
Galileo
 After the first Telescope was patented in the
Netherlands in 1608,Galileo happened to be there in
1609 and figured he could use it in his mathematical
studies.
- Telescope attributed to Galileo currently on display at the Griffith Observatory
Galileo (cont.)
 Galileo decided to ‘perfect’ the design after he
returned home, and after experimenting with
different lenses, he presented the finished product to
his benefactor who approved, and thus he began his
astronomical observations.
Fresco by Giuseppe Bertini depicting Galileo showing the
Doge of Venice how to use the telescope
The Theory - A
 Two methods stand out during the early
development. The first:

The Galilean Telescope - uses a convergent (plano-convex or
bi-convex) objective lens and a divergent (plano-concave or biconcave) eyepiece lens. Galilean telescopes produce upright
images.
The Theory - B
 Galilean Telescope
The Theory - B
 The second:
 The Keplerian Telescope – invented by Johannes Kepler in
1611, it is an improvement over the Galilean Telescope. It uses
a convex lens as the eyepiece instead of Galileo's concave one.
The advantage of this arrangement is the rays of light
emerging from the eyepiece are converging. This allows for a
much wider field of view and greater eye relief but the image
for the viewer is inverted.
The Theory - D
 Keplerian Telescope
How it is put together?
 For that, we ask our builder, James.
The Next Step
 Telescopes continued to
advance.
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Christiaan Huygens improved focus,
and with his brother, invented the
Aerial Telescope in 1675.
Newton’s Reflecting Telescope
(1666) –
"Cassegrain reflector" was devised in
1672 by Laurent Cassegrain –
Mount Wilson Observatory in 1908 -
Today’s Telescopes
 Telescopes come in several different types today:
 X-ray telescopes: Detect X-Rays, used to study the sun.
 Infrared telescopes: Use longer wavelengths than visible light.
 Gamma-Ray telescopes: Scan for gamma rays to map distant
stars.
 Radio telescopes: Scan distant parts of the universe by picking
up radio emissions.
The Biggest Telescope?
The largest Telescope in
the world might very well
be the Very Large Array.
It is a Radio Telescope
located in the Plains of San
Agustin, New Mexico.
Fully extended, it stretches
across 22 miles!
The world’s largest Optical Telescope
The Canaries Great Telescope, located in the Canary
Islands which are owned by Spain, is operated by the
Instituto de Astrofísica de Canarias (IAC). It is a
reflecting telescope with a mirror 34 feet wide, and it
became operational in 2009.
The Best Telescope?
The Hubble Space Telescope.
- A Cassegrain Reflector type automated telescope, located in
Low Earth Orbit.
- Able to detail objects at incredible distance with more
clarity than ever before observed.
- Answered many questions astronomers had for centuries.
What Telescopes Explore
“The Pillars of Creation” is a picture taken by the Hubble Space Telescope of a part of Messier
Object 16, the Eagle Nebula. Each ‘peak’ in the right image is the size of the Solar System!
 The pillars were destroyed by a Supernova approximately 7,000 years ago, but because of the
speed of light, we will not see it for another 1,000 years.
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References
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http://upload.wikimedia.org/wikipedia/commons/7/7d/Galileo_telescope_replica.jpg
http://upload.wikimedia.org/wikipedia/commons/e/e7/Bertini_fresco_of_Galileo_Galilei_and_Doge_of_Venice.jpg
http://galileo.rice.edu/lib/student_work/astronomy96/telescope_draw.gif
http://makezineblog.files.wordpress.com/2009/12/kepleriantelescope_cc.jpg?w=600&h=272
http://content.answcdn.com/main/content/img/McGrawHill/Encyclopedia/images/CE757724FG0010.gif
http://en.wikipedia.org/wiki/Gran_Telescopio_Canarias
http://galileo.rice.edu/lib/student_work/astronomy96/mtelescope.html
http://hubblesite.org/
http://www.nasa.gov/mission_pages/hubble/main/index.html
http://www.infoastro.com/200012/01grantecan.html